Survival Impact of Prolonged Treatment Duration in Primary Chemoradiation for Cervical Cancer

The negative impact of prolongation in radiation treatment time on local tumor control has been investigated in many tumor sites including head and neck, lung, breast and cervical cancers, with most studies revealing that prolonged treatment schedules are associated with inferior local control [1]. In a retrospective study of 1,224 patients with stage IB-III cervical cancer treated with radiation therapy, Perez et al. [2] demonstrated that every day of prolongation of treatment time beyond 30 days resulted in a 0.85% reduction in pelvic tumor control rate [2]. Similarly, Petereit et al. [2] demonstrated in a cohort of 209 cervical cancer patients undergoing primary radiation therapy that each additional day of treatment delay beyond 55 days was associated with a 0.7% loss of pelvic tumor control and a 0.6% reduction in survival [3]. Other retrospective studies report similar findings suggesting an approximately 1% (range 0.3-1.6%) loss of local tumor control for each day of prolongation of primary radiation therapy for cervical cancer [3]. Randomized controlled data are not available to identify the optimal treatment window in the primary treatment of cervical cancer. While one cannot ignore the potential interrelation of radiation treatment duration and confounding factors related to tumor anatomy, tumor biology, and tumor response, it has been well accepted that unnecessary delays and breaks in radiation therapy should be avoided. Based on a review of five large retrospective studies investigating the impact of treatment duration on the efficacy of radiation therapy in cervical cancer, it appears that overall treatment time should be limited to 56 days [2-7].